Hauser, president of the Center for Cetacean Research and Conservation, tells the Portland Press Herald that whales are "altruistic" and often hide seals from predators, but she has never experienced or read about anything about a whale protecting a human. "If someone told me the story, I wouldn't believe it," she said.

The Brunswick resident said she was oblivious to the shark during the tense, 10-minute encounter. The whale started to nudge her, and appeared to push her with its head. The animal also appeared to shield her with its pectoral fin.

Her research companions turned off an underwater video drone, fearing she was going to be mauled to death.

James Sulikowski, a marine biologist and professor at the University of New England who has studied tiger sharks, said he's not convinced that the whale saved her life. "The shark could have just been hanging around," he said. "There's really no way of knowing the whale's motivation."